Dry placer machine



March 3, 1931. I c, FISHER 1,795,017

DRY PLACER MACHINE Filed July 20, 1929 2 Sheets-Sheet l fyf y 7 X6 55 3 5 a 4 g V 3 5 a March 3, 1931. F|5HER 1,795,017

DRY PLACER MACHINE Filed July 20, 1929 2 Sheets-Sheet 2 7 M 6ZZe4 a 1mm Patented Mar. 3, 1931 UNITED STATES exams a. means. ornnuvm, oonomo nay PLACER moms":

Application filed July 20, 1929. Serial No. 879,735."

This invention relates to improvements inmachines for separating gold and other metal particles from gangue.

In many parts of our country there are large deposits of auriferous sands, which contain a considerable amount of gold and other valuable metals, but which are so located that there is very little if any water available, and for this reason the ordinary 1o methods of separation cannot be employed,

as these nearly always require water.

It is the object of this invention to produce a simple and substantial device that can be readily transported to any place where it is to be used and by means of which gold and other valuable metals can be separated from dry gangue or sand.

This invention, briefly described, consists of a bowl which is mounted for. rotation about a vertical axis that coincides with the axis of the bowl. The bottom of the bowl is provided with a downwardly extending tubular journal, while the inner surface of the bottom has a central upwardly extending projection that is provided with an opening which forms a continuation of the opening in thejournal.

One or more hoppers are supported above the bowl and are each provided with a feed pipe that terminates a short distance above the bottom of the bowl. These feed pipes are provided on their lower ends with notches which are located at the rear of the pipes when the bowl is rotated, and which, therefore, serve to deposit a continuous layer of sand on the bottom of the bowl. Means 18 provided for stirring the sand or gangue and for moving it outwardly towards the outer edge of the bowl, the excess of sand flowing out through the tubular journal and onto a conveyor which carries it away to a pump.

Having thus briefly described the invention, the same will now be described in detail. and for this purpose, reference will be had to the accompanying drawings in which the referred embodiment of the invention has een shown, and in which:

Fig. 1 is a side elevation of my improved device, a portion being broken away to better disclose the construction;

Fig. 2 is a top plan view of the machine Fig. 3 is a section taken on line 33, Fig. 1, looking into the bowl from the top; F Fig. 4 is a section taken on line 4.-4,

ig. 5 is a section taken on line 55, Fig. 3;

Fig. 6 is a section taken on line 6-6, Fig. 3 5 and shows the construction of the feed pipe; and

Fig. 7 is a plan view of the lower end of the feed pipe.

The machine is mounted on a truck having side members 1 whose rear ends are su ported from an axle 2 to the-outer ends of which are secured the rear wheels 3. The front ends of the side members 1 are connected by a curved bar 4 underneath of which is located the front axle 5. y The axle 5 is connected with the bar 4 by means of a bolt 6 and has wheels 7 connected to its outer ends. A tongue 8 serves to guide the truck when it is transported. Secured to the side members 1 are two spaced brackets 9. The lower ends of these brackets are secured to the side members 1 by means of bolts or rivets 10, and the upper ends are provided with bearings 11 and 12, in which the supporting frame 13 is journalled. The frame 13 is subtantially Ushaped and has its opposite sides provided with trunnions that project into and which are journalled in bearings 11 and 12. The trunnion that extends through the bearing 11 is hollow and serves as a bearing for a shaft 14 that is rotated by means of a motor 15 and is connected with the latter by means of a chain 16. A pinion 17 is connected to the inner end of shaft 14. The frame member 13 is provided with a bearing 18 that extends vertically through the base of theframe. se-

'25 and serves to hold the gear 19 against rotation. By turning the wheel 22 and the shaft 21, it is possible to rotate member 13.about its trunnions.

Supported on the frame 13 is a bowl 26 that has been shown in cross section in Fig. 4. This bowl has, a cylindrical wall extending upwardly from the curved bottom. 27.-

This bottom is provided with a tubular cylindrical journal 28 that extends downwardly from" the center thereof and is of the proper size to fit the bearing 18. A ball bearing which has been indicated by reference numeral 29 separates the upper end of bearing 18 from the bottom of the bowl and serves as a thrust bearing that carries the weight of the bowl and its contents during operation. The bowl is also provided with a central upwardly extending projection 30 that has a threaded opening 31 which is in axial alignment with the opening in journal 28. A nipple 32 is threaded on its outer surface and engages with cooperating threads on the wall of opening 31. The upper end of this nipple has an outwardly extending flange 33 and is held in adjusted position by a lock nut 34.

The cylindrical wall of the bowl has an annular gear 35 that is concentric with the tubular journal and is engaged by the pinion 17 so that when the latter is rotated by the engine 15, the bowlwill rotate about its axis. The frame member 13 has its parallel sides 4 36 provided at their upper ends with inwardly extending flanges 37 on which the plate 38 rests and to which it is secured by means of bolts 39. This plate is provided with two openings 40 through which the conical bottoms 41 of the hopper 42 extend. Brackets 43 are secured to the upper surface of plate 38 and support a steel band 44 that encircles the hopper and serves to steady the same.

Secured to the lower end of each conical bottom 41 is a feed pipe 45, which terminates a short distance above the inner surface of the bottom 27. The lower ends of these pipes are oft-he shape shown in Fig. 7 and the vertex, which has been indicated by reference numeral 46, is to the front of the pipe when its movement with respect to the bowl is considered. The rear wall of each pipe is provided with a notch 47 through which the gangue or sand and metal mixture may pass from the interior of the pipe and be deposited on the bottom of the rotating bowl. In the embodiment illustrated, there are two feed pipes which are located at diametrically opposite points, but there may be only one, or

there may be a larger number, depending upon the size and the capacity of the apparatus. Secured to plate 38 are supporting bars of channel shape which have been designated by reference numeral 48. These bars are firmly secured to plate 38 by means of bolts 49, and have their flanges provided with spaced openings for the reception of the tapered shanks 50 of the blades 51 that serve to stir the material. These blades are held in adjusted position by means of nuts 52. The blades are so located that the centersof the circles passing through the shanks 50 are concentric with the bowl and those that pass through the shanks on one side of plate 38 lie about half ways between the shanks on the other side so that the blades on the two sides are staggered. The bottom of the bowl is provided with a plurality of grooves 53 that terminate in circular depressions 54. Mercury is contained in depressions 54 and when the gold or other metallic values contained in the gangue are deposited in the grooves53 they will finally travel downwardly and come in contact with the mercury so as to form an amalgam.

\Vith the parts assembled and arranged in the manner described let us assume that the hopper 42 is tilled with a dry mixture of sand'or gangue and gold in a finely divided state. And let us further assume that the engine is operating so as to rotate the bowl in the direction indicated by the arrows in Fig. 3. As the bowl rotates, the contents of the hoppers will be delivered to the bottom of the bowl through the feed pipes 45 and as the bowl rotates a continuous layer of the material to be treated is deposited on the bottom of the bowl. As the bowl rotates, the blades 51 will stir the material and as these are inclined, in the manner shown in Fig. 3, the material will be movedoutwardly towards the wall of the bowl, and will, as a consequence. build up to a considerable height along the outer wall. ."When the material accumulates in the bowl above a certain level, the surplus will pass outwardly through the opening in the nipple 32 and thence downwardly through the journal 28 and onto the conveyor 55 which conveys the gangue to a dump. After the gangue leaves the conveyor, it can be subjected to treatment in some other type of apparatus if this should be deemed to be desirable In the drawing I have not shown any mechanism for elevating the ore into the hopper as this does not form part of my invention. but I want to call attention to the fact that I intend to employ a conventional rotary screen for separating the larger particles from the smaller and an ordinary conveyor for elevating the material into the hopper. It is, of course, possible to operatethe machine by shoveling material into the hopper by hand, but where possible proper power operated machinery should be employed for this purpose.

I want to call especial attention to the fact that by means of the construction described, the material is introduced into the bowl adjacent the bottom thereof, and therefore any gold or other metal that is mixed with the gangue is immediately deposited at or near the bottom so that the operation does not necessitate a settling of the values, but rather produces an upward movement of the gangue which leaves the values at the bottom. The feature just mentioned is considered to be of extreme importance in a machine of this type as it is obviously much easier to efiect a separation when the mixture is deposited at the bottom of the bowl than if it were deposited at the top andagitation were de pended on to cause the heavier particles to travel towards the bottom. Experiment has demonstrated that when sand and gold particles are deposited on a surface, in the man ner shown in the drawing and described herein, no difiiculty whatever is experienced in retaining the values on the bottom while the gangue travels upwardly in response to the additional introduction for material at this point.

The blades 51. as above explained, serve to stir the material and to move it outwardly against the outer wall, and in addition to this short pieces of chain or other equivalent devices may be attached to the bottom of the feed pipe directly back of opening 27 so as to increase the stirring effect, if this should be found necessary.

For the purpose of facilitating the cleaning of the apparatus after a run has been made, the tilting mechanism comprising the hand wheel 22 and the pinion 20 has been provided.

Although this machine has been designed primarily for use with dry placer m1n1ng, 1t is also suitable. for use where water is madable, in which case the ore is mixed with water so as to form a pulp and as this pulp is introduced into the bowl near the bottom thereoi, the values will remain on the bottom, while the gaugue in the pulp travels up wardly and overflows through the discharge opening in the center of the bowl.

Having described the invention what 1s claimed as new is:

1. In a device of the class described, in combination, a support, a bowl carried by the support and mounted for rotation about a substantially vertical axis, said bowl having atubular journal whose upper end terminates a short distance above the bottom of the bowl, and a bottom whose upper surface is free from projections, means for rotating the bowl, a feed hopper located above the bowl, a feed pipe extending from the hopper to a point directly above the bottom of the bowl, the following side of the pipe having a notch whereby when the bowl is rotated, a continuous layer of material will be deposited on the bottom of the bowl, a plurality of stirrer blades secured to a stationary support and terminating adjacent the upper surface of the bottom and means for adjusting the height of the upper end of the tubular journal.

2. A device of the class described, comprising, in combination, a support provided with a vertical opening forminga bearing, a bowl provided with a downwardly extending tubular journal adapted to extend into the vertical opening, the bowl having a conical projection concentric with the journal and extending upwardly from the bottom, the conical projection having an opening which is a continuation of the opening in the journal and which forms an overflow outlet, means for rotating the bowl, means for continuously depositing a mixture of gangue and metal values on the bottom of the bowl when the latter is rotated, means for stirrin the material in contact with the bottom a ter it has been deposited thereon, and means for ad justing the position of the upper end of the opening in the journal.

3. A device for separating metal values from gangue comprising, in combination, a bowl having a tubular journal extending downwardly from the underside thereof, the inner surface of the bowl projecting upwardly and having an opening that forms a continuation of the opening in the journal, a threaded tubular nipple in the opening in the projection, means for holding the nipple in adjusted position, the bottom of the bowl having a plurality of grooves for the reception of mercury, a supporting frame having a bearing for the reception of the journal, means for rotating the bowl about the axis of the journal, a hopper supported above the bowl and having a pipe that extends downwardly therefrom and terminates adjacent the bottom of the bowl, the lower end of the pipe having a notch on the rear side whereby when the bowl is rotated, a layer of gangue and metal will be deposited on the bottom of the bowl, and means for stirring the material in contact with the bottom of the bowl while the latter rotates.

4. A device for separating metal values from gangue comprising, in combination, a bowl having a tubular journal extending downwardly from the underside thereof, the inner surface of the bowl projecting upwardly and having an opening that forms a continuation of the opening in the journal, a threaded tubular nipple in the opening in the projection, means for holding the nipple in adjusted position, the bottom of the bowl having a plurality of grooves for the recep tion of mercury, a supporting frame having a bearing for the reception of the journal, means for rotating the bowl about the axis of the journal, a hopper supported above the bowl and having a pipe that extends downwardly therefrom and terminates adjacent the bottom of the bowl, the lower end of the pipe having a notch on the rear side whereby when the bowl is rotated, a layer of angue and metal will be deposited on the ottom of the bowl, means for stirring the material in contact with the bottom of the bowl while the latter rotates, a plurality of stirrers extending downwardly into the bowl, and means for holding the stirrers in adjusted position.

In testimony whereof I afiix my signature.

CHARLES E. FISHER. 

